U.S. patent application number 17/195113 was filed with the patent office on 2021-09-09 for rotary mower with cutting deck with bidirectional cutting blades.
The applicant listed for this patent is The Toro Company. Invention is credited to Jason J. Henry, Chris A. Wadzinski.
Application Number | 20210274711 17/195113 |
Document ID | / |
Family ID | 1000005481546 |
Filed Date | 2021-09-09 |
United States Patent
Application |
20210274711 |
Kind Code |
A1 |
Henry; Jason J. ; et
al. |
September 9, 2021 |
ROTARY MOWER WITH CUTTING DECK WITH BIDIRECTIONAL CUTTING
BLADES
Abstract
A rotary lawn mower has one or more grass cutting blades that
are rotatable in opposite directions about a vertical axis or axes.
Each blade is double edged having front and rear cutting edges on
each end of the blade. Each blade end has a front sloped face
inboard of the front cutting edge and a rear sloped face inboard of
the rear cutting edge. These faces create air flow within the
cutting chamber when cutting grass regardless of the direction of
rotation of the blade. The direction of rotation of each blade is
reversed to switch between discharge and mulching modes of
operation. A flow director has a curved vertical guide wall that
guides the grass clippings through a discharge opening in the
discharge mode and that guides the flow of grass clippings away
from the discharge opening in the mulching mode.
Inventors: |
Henry; Jason J.; (Lakeville,
MN) ; Wadzinski; Chris A.; (Inver Grove Heights,
MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Toro Company |
Bloomington |
MN |
US |
|
|
Family ID: |
1000005481546 |
Appl. No.: |
17/195113 |
Filed: |
March 8, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62987086 |
Mar 9, 2020 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A01D 34/76 20130101;
A01D 34/73 20130101; A01D 42/005 20130101; A01D 34/667
20130101 |
International
Class: |
A01D 42/00 20060101
A01D042/00; A01D 34/76 20060101 A01D034/76; A01D 34/66 20060101
A01D034/66; A01D 34/73 20060101 A01D034/73 |
Claims
1. A rotary lawn mower, which comprises: (a) a cutting deck
comprising a top wall and a peripheral skirt extending downwardly
from the top wall, the top wall and peripheral skirt forming a
cutting chamber having an open bottom face, the cutting chamber
having a discharge opening located at least partially in the
peripheral skirt of the deck for allowing grass clippings to exit
from the cutting chamber; (b) at least one cutting blade located
within the cutting chamber with the at least one blade being
rotatable about a substantially vertical axis of rotation, each end
of the at least one blade comprising: (i) a front cutting edge and
a rear cutting edge, and (ii) an upwardly raised, front sloped face
inboard of the front cutting edge and an upwardly raised, rear
sloped face inboard of the rear cutting edge; and (c) a reversible
blade drive for allowing a user to select either: (i) a discharge
mode of operation in which the at least one blade rotates in a
first direction about the axis of rotation with the front cutting
edges being leading edges and the rear cutting edges being trailing
edges, or (ii) a mulching mode of operation in which the at least
one blade rotates in a second opposite direction about the axis of
rotation with the rear cutting edges being leading edges and the
front cutting edges being trailing edges.
2. The mower of claim 1, wherein each end of the at least one blade
comprises at least one opening extending through a thickness of the
at least one blade to permit the passage of air through the at
least one opening, wherein the at least one opening in each end of
the blade is located between the front and rear cutting edges on
each end of the blade.
3. The mower of claim 2, wherein the at least one opening comprises
a radial slot.
4. The mower of claim 3, wherein the front and rear sloped faces on
each end of the at least one blade are inboard of the front and
rear cutting edges.
5. The mower of claim 2, wherein the front and rear sloped faces
have substantially the same angle of inclination as one
another.
6. The mower of claim 2, wherein the front and rear sloped faces
have a substantially constant height relative to the front and rear
cutting edges.
7. The mower of claim 1, wherein the front sloped face has an
inclination of at least approximately 60.degree. at a tip of each
end of the at least one blade.
8. The mower of claim 1, wherein the front sloped face is steeper
than the rear sloped face.
9. The mower of claim 8, wherein the front sloped face is at least
approximately three times steeper than the rear sloped face at a
tip of each end of the at least one blade.
10. The mower of claim 9, further including a raised ridge on each
end of the at least one blade located between the front and rear
cutting edges, wherein the front sloped face is formed by a surface
extending between the front cutting edge of the at least one blade
and a crest of the ridge and the rear sloped face is formed by a
surface extending between the rear cutting edge of the at least one
blade and the crest of the ridge.
11. The mower of claim 10, wherein the ridge gradually decreases in
height relative to the cutting edges as the ridge extends radially
inwardly from the tip of each end of the at least one blade.
12. The mower of claim 11, wherein the ridge disappears at radial
inner ends of the cutting edges.
13. The mower of claim 1, wherein the at least one blade comprises
two or more blades with each blade being rotatable about its own
separate substantially vertical axis of rotation.
14. The mower of claim 1, wherein the cutting chamber has a
substantially vertical, curved guide wall therein adjacent the
discharge opening, the guide wall presenting an outward curvature
to grass clippings that have been generated in the discharge mode
to direct such clippings outwardly through the discharge opening,
and the guide wall further presenting an inward curvature to grass
clippings that have been generated in the mulching mode to direct
such clippings inwardly in the cutting chamber away from the
discharge opening.
15. The mower of claim 14, wherein the cutting chamber has a
substantially horizontal floor along a bottom edge of the curved
guide wall extending between the curved guide wall and the
peripheral wall of the cutting chamber.
16. The mower of claim 14, wherein the guide wall and the floor are
formed as part of a single piece flow director that is separate
from the cutting deck, and further including fasteners for
removably mounting the flow director to the cutting deck adjacent
the discharge opening.
17. A rotary lawn mower, which comprises: (a) a cutting deck
comprising a top wall and a peripheral skirt extending downwardly
from the top wall, the top wall and peripheral skirt forming a
cutting chamber having an open bottom face, the cutting chamber
having a discharge opening located at least partially in the
peripheral skirt of the deck for allowing grass clippings to exit
from the cutting chamber; (b) at least one cutting blade located
within the cutting chamber with the at least one blade being
rotatable about a substantially vertical axis of rotation, each end
of the at least one blade comprising a front cutting edge and a
rear cutting edge; (c) a reversible blade drive for allowing a user
to select either: (i) a discharge mode of operation in which the at
least one blade rotates in a first direction about the axis of
rotation with the front cutting edges being leading edges and the
rear cutting edges being trailing edges, or (ii) a mulching mode of
operation in which the at least one blade rotates in a second
opposite direction about the axis of rotation with the rear cutting
edges being leading edges and the front cutting edges being
trailing edges; and (d) wherein the cutting chamber has a
substantially vertical guide wall therein adjacent the discharge
opening, the guide wall presenting an outward side to grass
clippings that have been generated in the discharge mode to direct
such clippings outwardly through the discharge opening, and the
guide wall further presenting an inward side to grass clippings
that have been generated in the mulching mode to direct such
clippings inwardly in the cutting chamber away from the discharge
opening.
18. The mower of claim 17, wherein the cutting chamber has a
substantially horizontal floor along a bottom edge of the guide
wall extending between the guide wall and the peripheral wall of
the cutting chamber.
19. The mower of claim 18, wherein the guide wall and the floor are
formed as part of a single piece flow director that is separate
from the cutting deck, and further including fasteners for
removably mounting the flow director to the cutting deck adjacent
the discharge opening.
20. The mower of claim 17, wherein the at least one blade comprises
two or more blades mounted within the cutting chamber with each
blade being rotatable about its own separate substantially vertical
axis of rotation.
Description
TECHNICAL FIELD
[0001] This invention relates to a cutting deck for mowers having a
plurality of rotary cutting blades for cutting a swath of grass
that is wider than the swath cut by any single blade and to a mower
equipped with such a cutting deck. More particularly, this
invention relates to such a cutting deck having multiple modes of
discharge of the grass clippings generated by the operation of the
blades.
BACKGROUND OF THE INVENTION
[0002] Rotary mowers which employ a cutting deck to house multiple
rotary cutting blades that rotate about vertical axes are well
known for cutting grass. The deck is carried by a traction frame
for propelling the deck over the ground and for powering the
cutting blades. The traction frame may comprise a ride on unit
which carries the operator in a sitting and/or standing position
during operation of the mower. Alternatively, the traction frame
may comprise a walk behind unit in which the operator walks on the
ground behind the traction frame during operation of the mower. In
some cases, the traction frame may be remotely controlled by an
operator or may operate in an autonomous manner under the control
of an electronic microprocessor based controller.
[0003] The cutting blades carried in the deck are typically
staggered fore-and-aft relative to one another. This permits the
orbits of the blades to avoid hitting one another but to be
slightly overlapped with one another to allow the blades to
collectively cut a swath of grass that is wider than the swath cut
by any single blade. Alternatively, the blades may be arranged
directly side-by-side relative to one another with the orbits of
the blades slightly overlapping to again cut a swath of grass that
is wider than the swath cut by any single blade. However, in this
direct side-by-side arrangement of the blades, the rotation of the
blades must be timed to prevent the blades from hitting one another
as they rotate.
[0004] The grass clippings generated by the operation of the blades
may be discharged from the cutting deck in various modes. For
example, the side discharge mode throws the clippings laterally
from the deck through a side discharge opening located in a side
wall of the deck. The mulching mode comprises the discharge of the
clippings downwardly into the cut grass swath through an open
bottom face of the deck. Some decks may also include a rear
discharge mode in which the clippings are thrown rearwardly through
a rear discharge opening. One or more of these modes may be
incorporated into any given deck as desired.
[0005] In known rotary cutting decks having multiple discharge
modes, e.g., both side discharge and mulching modes, some structure
is normally provided for blocking the side discharge opening when
the user wishes to operate in the mulching mode. This structure
varies but often includes a selectively pivotal plate or door that
closes the side discharge opening during operation in the mulching
mode. In some cases, a closure member must be manually installed in
the side discharge opening as part of a mulching kit rather than
using a pivotal plate or door. In other cases, the pivotal plate or
door is permanently installed in the deck and is swung between open
and closed positions by the operator using a manually operable
mechanical linkage or an electric motor kit. Regardless of how one
closes the side discharge opening, the need for some type of
closure and the operation or installation of such closure increases
the expense of manufacturing the deck. Moreover, when a mulching
kit is used that must be manually installed to mulch and must then
be manually removed for side discharge, the burden on the operator
in shifting between the different modes is significant.
[0006] Accordingly, there is a need in the art to provide a rotary
cutting deck that is optimized for operation in the side discharge
and mulching modes with the operator having the ability to quickly
and easily shift between the modes. This invention is directed to
satisfying this need.
SUMMARY OF THE INVENTION
[0007] One aspect of this invention relates to a rotary lawn mower
having a cutting deck comprising a top wall and a peripheral skirt
extending downwardly from the top wall. The top wall and peripheral
skirt form a cutting chamber having an open bottom face. The
cutting chamber has a discharge opening located at least partially
in the peripheral skirt of the deck for allowing grass clippings to
exit from the cutting chamber. At least one cutting blade is
located within the cutting chamber with the at least one blade
being rotatable about a substantially vertical axis of rotation.
Each end of the at least one blade comprises a front cutting edge
and a rear cutting edge, an upwardly raised, front sloped face
inboard of the front cutting edge, and an upwardly raised, rear
sloped face inboard of the rear cutting edge. A reversible blade
drive is provided for allowing a user to select either a discharge
mode of operation in which the at least one blade rotates in a
first direction about the axis of rotation with the front cutting
edges being leading edges and the rear cutting edges being trailing
edges or a mulching mode of operation in which the at least one
blade rotates in a second opposite direction about the axis of
rotation with the rear cutting edges being leading edges and the
front cutting edges being trailing edges.
[0008] Another aspect of this invention relates to a rotary lawn
mower which comprises a cutting deck comprising a top wall and a
peripheral skirt extending downwardly from the top wall. The top
wall and peripheral skirt form a cutting chamber having an open
bottom face. The cutting chamber has a discharge opening located at
least partially in the peripheral skirt of the deck for allowing
grass clippings to exit from the cutting chamber. At least one
cutting blade is located within the cutting chamber with the at
least one blade being rotatable about a substantially vertical axis
of rotation. Each end of the at least one blade comprises a front
cutting edge and a rear cutting edge. A reversible blade drive
system is provided for allowing a user to select either a discharge
mode of operation in which the at least one blade rotates in a
first direction about the axis of rotation with the front cutting
edges being leading edges and the rear cutting edges being trailing
edges or a mulching mode of operation in which the at least one
blade rotates in a second opposite direction about the axis of
rotation with the rear cutting edges being leading edges and the
front cutting edges being trailing edges. The cutting chamber has a
substantially vertical guide wall therein adjacent the discharge
opening. The guide wall presents an outward side to grass clippings
that have been generated in the discharge mode to direct such
clippings outwardly through the discharge opening. The guide wall
further presents an inward side to grass clippings that have been
generated in the mulching mode to direct such clippings inwardly in
the cutting chamber away from the discharge opening.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] This invention will be described more fully in the following
Detailed Description, when taken in conjunction with the following
drawings, in which like reference numerals refer to like elements
throughout.
[0010] FIG. 1 is a perspective view of a rotary mower equipped with
a rotary cutting deck according to one embodiment of this
invention;
[0011] FIG. 2 is a top plan view of the cutting deck shown in FIG.
1;
[0012] FIG. 3 is a bottom plan view of the cutting deck shown in
FIG. 1;
[0013] FIG. 4 is a perspective view of one of the cutting blades
used in the cutting deck shown in FIG. 1;
[0014] FIG. 5 is a side elevational view of the cutting blade shown
in FIG. 4;
[0015] FIG. 6 is a perspective view of the cutting deck shown in
FIG. 1, particularly illustrating a flow director for the grass
clippings generated by the operation of the cutting deck with the
flow director being shown exploded away from a typically sized and
shaped side discharge opening in a side wall of the deck in which
the flow director is to be installed;
[0016] FIG. 7 is a perspective view similar to FIG. 6, particularly
illustrating the flow director installed in the side discharge
opening in the side wall of the cutting deck;
[0017] FIG. 8 is a perspective view from the front of the flow
director shown in FIGS. 6 and 7 looking at the exterior of the flow
director;
[0018] FIG. 9 is a perspective view similar to FIG. 8 looking at
the interior of the flow director;
[0019] FIG. 10 is a perspective view of an alternative cutting
blade which may be used in the cutting deck shown in FIG. 1;
and
[0020] FIG. 11 is a side elevational view of the cutting blade
shown in FIG. 10.
DETAILED DESCRIPTION
[0021] FIG. 1 illustrates a rotary mower 2 equipped with one
embodiment of a rotary cutting deck 4 according to this invention.
Mower 2 has a traction frame 6 that is supported for rolling over
the ground by a pair of front caster wheels 8 and by a pair of rear
drive wheels 10. A prime mover (not shown) or other source of power
is carried on traction frame 6 to self-propel mower 2 by rotating
drive wheels 10 and to provide power to rotate various rotary
cutting blades 12 carried on deck 4. Deck 4 is mounted to traction
frame 6 in a manner well known in the art in a mid-mount position
between front wheels 8 and rear wheels 10.
[0022] Traction frame 6 preferably includes a seat 14 for carrying
an operator in a seated position. Alternatively, traction frame 6
could be a stand-on type in which the operator is carried in a
standing position on a rear foot platform provided on traction
frame 6. In addition, traction frame 6 may also be a walk behind
frame, a remotely controlled frame, or an autonomous, self-guiding
frame. Thus, the type of mower 2 to which deck 4 is attached is not
important to this invention.
[0023] Referring now to FIGS. 2 and 3, deck 4 comprises a top wall
16 and a peripheral skirt 18 extending downwardly for a short
distance from the outer edges of top wall 16. Skirt 18 is
substantially continuous except for a first side discharge opening
20 shown in FIG. 6 provided in one of the lateral side walls of
skirt 18. A typical side discharge chute 22 having a downwardly
facing U-shape is attached to deck 4 and extends outwardly from
first opening 20 to shield bystanders from the flow of grass
clippings or any thrown objects which are being discharged from
deck 4. The bottom face of deck 4 is open towards the ground. Skirt
18 has a substantially linear front wall 24 which mounts a pair of
laterally spaced anti-scalp wheels or rollers 26.
[0024] As best shown in FIG. 3, the underside of deck 4 carries two
laterally spaced blades 12 beneath top wall 16 and within skirt 18
of deck 4. Deck 4 has a scalloped rear wall having a pair of
semicircular sections 25 which partially surround the rear portions
of the orbits of blades 12. In the embodiment shown herein, blades
12 are staggered fore-and-aft relative to one another with the
inner portions of the orbits of blades 12 slightly overlapping one
another. Thus, blades 12 will cut a single, unbroken swath of grass
that is wider than the swath that would have been cut by either
blade 12 alone. Alternatively, blades 12 could be arranged directly
side-by-side with the inner portions of the orbits of blades 12
slightly overlapping one another. However, in this alternative
blade arrangement, a timed drive system would be required to rotate
blades 12 out of phase with one another to ensure that blades 12
never hit one another in the overlap region.
[0025] Preferably, blades 12 are powered by individual electric
motors 27 which are powered by a source of electric power carried
on traction frame 6. Thus, motors 27 are reversible at the click of
a switch to change the direction of rotation of blades 12 without
there being any cost incurred other than for the switch. While
electric motors are disclosed, hydraulic motors could also be used
supplied by pressurized hydraulic oil generated by a hydraulic
system on traction frame 6 along with a valve to reverse the
direction of oil flow when so desired. In addition, a reversible
belt and pulley drive system or some other reversible mechanical
drive system could be used as well.
[0026] Referring now to FIGS. 4-5, each blade 12 has an elongated
rectangular shape with opposite ends. Each blade 12 is identical.
Thus, a description of one blade 12 will suffice to describe the
other blade 12.
[0027] Each end 28 of blade 12 is double edged with a sharpened
cutting edge A located on a front face and a sharpened cutting edge
B located on a rear face. The lengths of cutting edges A and B are
substantially the same as one another and may comprise about two to
four inches. Ends 28 of blades 12 are also inclined slightly
downwardly. Thus, cutting edges A and B are not purely horizontal
relative to the horizontal central section of blade 12, but incline
slightly downwardly relative to the central section 29 of blade 12
as they extend outwardly at an angle of about 5.degree..
[0028] Blade 12 has an upwardly extending ridge 30 between cutting
edges A and B. Ridge 30 has a crest 32 which is generally parallel
to cutting edges A and B. However, ridge 30 is asymmetric relative
to cutting edges A and B with crest 32 of ridge 30 being closer to
cutting edge A than crest 32 is to cutting edge B. As a result, the
sloped transition between cutting edge A and crest 32 necessarily
forms a short and steeply inclined face C. Correspondingly, the
sloped transition between cutting edge B and crest 32 forms a face
D that is necessarily longer and substantially more gently inclined
as a result.
[0029] In one embodiment of blade 12, the angle .alpha. of
inclination of face C is approximately 60.degree. at the tip 34 of
blade 12 while the angle .beta. of face D is approximately
20.degree. at blade tip 34. In this embodiment, face C is
approximately three times steeper than face D at blade tip 34 over
the same rise of crest 32. The rise of crest 32 gradually decreases
as ridge 30 extends inwardly from blade tip 34 with ridge 30
disappearing at radial inner ends of cutting edges A and B.
[0030] Referring now to FIG. 6, first opening 20 is of the general
size and shape typically found on prior art rotary mowers for the
passage of grass clippings in a side discharge mode of operation.
However, in this invention, a flow director 38 is mounted within
and remains within first opening 20 during operation of mower 2.
Flow director 38 is preferably molded as a single piece from a
relatively hard and durable plastic material and is mounted in any
suitable fashion, e.g. by threaded fasteners such as bolts or
screws or by bungee cords or some other structure which does not
require the use of tools, to the portions of deck 4 adjacent first
opening 20. This is done primarily for the sake of convenience and
cost savings. However, the geometry and functions provided by flow
director 38 could alternatively be designed as part of deck 4 and
would thus be built as an integral part of deck 4 during the
manufacture of deck 4.
[0031] As further shown in FIGS. 6 and 7, flow director 38 provides
a second side discharge opening 40 at a front end of flow director
38 which second opening effectively replaces first opening 20.
Second opening 40 is located at the exit or grass clippings
discharge end of front wall 24 of deck 4 when deck 4 is operating
in the side discharge mode. However, second opening 40 is reduced
in height and length compared to first opening 20.
[0032] The rest of flow director 38 downstream of second opening 40
is solid and fills in the rest of first opening 20 with downstream
being taken with reference to the direction of rotation of the
blade 12 adjacent flow director 38 when deck 4 is operating in the
side discharge mode. As flow director 38 extends downstream away
from second opening 40 when deck 4 is operating in the side
discharge mode, it forms a generally L-shaped, curved baffle 42
having a substantially horizontal floor 44 and a substantially
vertical, upwardly extending interior guide wall 46. The curved
guide wall 46 progressively decreases in height and floor 44
progressively decreases in width as flow director 38 extends
downstream away from second opening 40 as best shown in FIG. 6.
Eventually, baffle 42 disappears adjacent a rear end of flow
director 38 with the rear end of guide wall 46 being radially
outboard of the front end of guide wall 46. Blade 12 adjacent flow
director 38 is positioned to rotate beneath floor 44 of baffle 42
with blade 12 never hitting or striking any portion of flow
director 38.
[0033] Referring now to FIG. 3 illustrating the side discharge mode
of operation, second opening 40 in flow director 38 is always open
to the passage of the grass clippings being generated by blades 12.
Each blade 12 is rotated in the same counter-clockwise direction
CCW so that cutting edges A are cutting grass. The steeply inclined
faces C behind cutting edges A act as effective sails or vanes for
creating an air flow within deck 4 that is directed along the
inside of front wall 24 of skirt 18 of deck 4 in the direction of
the arrows E in FIG. 3. This air flow E feeds substantially
directly into second opening 40 provided by flow director 38. Thus,
the grass clippings generated by cutting edges A and B during the
counter-clockwise CCW rotation of blades 12 are quickly and
efficiently thrown through second opening 40. Once the grass
clippings pass through second opening 40, the grass clippings flow
along floor 44 and guide wall 46 of baffle 42 and are progressively
forced and ejected to the side of deck 4 by the outward curvature
of the outer face of guide wall 46 of baffle 42 as further shown by
the arrow E in FIG. 8.
[0034] Referring now to FIGS. 3 and 9, the same L-shaped baffle 42
described above in flow director 38 provides an opposite function
in the mulching mode of operation. Now, the inner face of vertical
guide wall 46 of baffle 42 provides an inwardly curved surface
taken with respect to the direction the grass clippings are being
circulated in the mulching mode of operation.
[0035] Deck 4 can be easily placed into its mulching mode of
operation by reversing the direction of rotation of blades 12 so
that blades 12 both rotate in a clockwise direction CW in FIG. 3.
In this direction, cutting edges B of blades 12 are the edges which
are cutting the grass. The gently inclined slope of the face D that
follows the edges B is also a relatively ineffective air flow
generating sail. Moreover, the grass clippings entrained in the
lessened air flow generated by the faces D, i.e., primarily the
clippings from the blade 12 closest to flow director 38 as the
clippings generated by the other blade 12 are not circulated near
flow director 38, are directed inwardly towards the middle of deck
4 by the increasingly inward protrusion of the curved inner face of
guide wall 46 of baffle 42 as shown by the arrow F in FIGS. 3 and
9. In addition and as best shown in FIG. 3, the curvature of the
semi-circular portion 25 surrounding the other blade 12 also acts
to direct clippings from such blade back towards the middle of deck
4 as shown by arrow G in FIG. 3. Thus, with the reversal in
direction of the bidirectional blades 12 to the clockwise CW
direction in FIG. 3 required for mulching, the grass clippings will
substantially be directed inwardly and drop out of deck 4 through
the open bottom face of deck 4 due to reduced air flow near the
center of blades 12. Such grass clippings act as mulch in the cut
grass swath rather than being thrown out through second opening 40
in flow director 38.
[0036] Referring again to FIG. 3 and when side discharge is
desired, the counter-clockwise direction CCW of rotation of blades
12 is selected. The grass clippings being generated by blades 12
are thrown along front wall 24 of skirt 18 and will pass through
second opening 40 provided by flow director 38 and then be ejected
laterally under discharge chute 22. When mulching is desired, a
clockwise CW direction of rotation of blades 12 in FIG. 3 is
selected. The grass clippings then being generated by blades 12
will be recirculated within deck 4 until they are driven downwardly
through the open bottom face of deck 4. During mulching the
clippings are simply not directed at second opening 40 provided by
flow director 38 and thus do not enter in any significant number
the side discharge path provided by flow director 38.
[0037] Accordingly, switching between side discharge and mulching
modes of operation is as easy as activating a switching device of
some type to change the direction of rotation of the bidirectional,
double edged blades. The convenience in which an operator can
switch or toggle between side discharge and mulching modes of
operation provides the operator with greater ease of operation. The
operator no longer needs to manually install a mulching kit to use
during mulching with the operator having to remove the mulching kit
when side discharge is desired. In decks where structure is carried
on deck 4, such as pivotal doors or plates that can be swung to a
closed position to block the side discharge opening to enter into
the mulching mode, the operator no longer needs to activate the
linkages that control such doors or plates. Moreover, such movable
and separately activated blocking structure is no longer
required.
[0038] Referring now to FIGS. 10 and 11, an alternative blade 52 is
depicted which may be used in place of each blade 12 described
herein. Like blade 12, each blade 52 has an elongated rectangular
shape with opposite ends. Each blade 52 is identical. Thus, a
description of one blade 52 will suffice to describe the other
blade 52.
[0039] Each end 54 of blade 52 is double edged with a sharpened
cutting edge A' located on a front face and a sharpened cutting
edge B' located on a rear face. The lengths of cutting edges A' and
B' are substantially the same as one another and may comprise about
two to four inches. Ends 54 of blades 52 are also inclined slightly
downwardly. Thus, cutting edges A' and B' are not purely horizontal
relative to the horizontal central section of blade 52, but incline
slightly downwardly relative to the central section 56 of blade 52
as they extend outwardly at an angle of about 5.degree.. A mounting
hole 58 or any other suitable mounting is provided in central
section 56 of blade 52 to allow blade 52 to be bolted or otherwise
secured to the vertical downwardly extending drive shaft of one of
the drive motors 27.
[0040] Each end 54 of blade 52 has a radial opening or slot 60
located between cutting edges A' and B'. Each slot 60 extends
completely through the thickness of blade 52. Each slot 60 also
extends radially inwardly from the tip of each end of blade 52 for
a length approximately equal to the length of cutting edges A' and
B'.
[0041] An upwardly extending, airflow generating sloped face C' is
formed in each end of blade 52 by an upwardly bent portion of blade
52 that is inboard of cutting edge A'. Similarly, an upwardly
extending, airflow generating sloped face D' is formed in each end
of blade 52 by an upwardly bent portion of blade 52 that is inboard
of cutting edge B'. Sloped faces C' and D' are substantially
identical to one another. For example, each sloped face C' or D' is
inclined upwardly at the same angle .theta. of approximately at
least 60.degree. or more. In addition, each sloped face C' or D'
has a constant height relative to its adjacent cutting edge A' or
B' between a radially outer end of each sloped face C' or D' and a
radially inner end of each sloped face C' or D'. Accordingly,
sloped faces C' and D' are symmetrical relative to one another
along opposite sides of radial slot 60.
[0042] The Applicants currently believe that the radial slots 60 on
each end of blade 52 extending as shown in FIGS. 10 and 11 allow
air to flow more easily through each end of blade 52. This is
believed to provide enhanced lift by sloped faces C' or D', each of
which acts as an airflow generating sail, when cutting edge A' or
B', respectively, is the leading edge of blade 52 taken with
respect to the direction of rotation. While cutting blade 12
described earlier herein also provides better performance in this
invention over standard blades known in the art, it is currently
thought that cutting blade 52 may provide even better performance
than cutting blade 12. Rather than use a radial slot 60 on each end
54 of blade 52, one or more openings or holes could be formed or
drilled in each end 54 of blade 52 to permit the passage of air
through each end 54 of blade 52.
[0043] Various modifications of this invention will be apparent to
those skilled in the art. For example, while the blade tip
configurations for the tips of blades 12 or 52 and the flow
director 38 are preferably used together in the same deck 4, each
could be used in deck 4 or other rotary cutting decks without using
the other. Moreover, the blade tip configurations for the tips of
blades 12 or 52 and the flow director 38 could be used together or
individually in a rotary cutting deck having a single blade 12 or
52, a rotary cutting deck having more than two blades 12 or 52,
and/or a rotary cutting deck having an additional third mode of
operation comprising a rear discharge mode for throwing the grass
clippings rearwardly from deck 4.
[0044] In addition, each blade 12 or 52 could comprise an assembly
of two single edged blades laid on top of another and mounted on
the drive shaft of a single motor 27. Each single edged blade would
have its cutting edges disposed oppositely to the cutting edges on
the other blade so that one blade in the two blade assembly would
cut grass in the clockwise direction of rotation of the blade
assembly while the other blade in the two blade assembly would cut
grass in the counter-clockwise direction of rotation of the blade
assembly. Any given single edged blade in the two blade assembly
would preferably have an upwardly raised face inboard of each of
its cutting edges to act as an airflow generating sail when the
cutting edges on a given single edged blade are being used to cut
grass. In such a two blade assembly, the overlaid single edged
cutting blades could be angularly offset relative to one another in
an X-shape or the like.
[0045] Accordingly, this invention is not limited to the details of
the embodiment specifically described and illustrated herein.
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